Metal foil perforator for capacitor winding machines



April 22, 1952 H. DAHL ETAL 2,593,993

METAL FOIL PERFQRATOR FOR CAPACITOR WINDING MACHINES Filed July 8, 19484 Sheets-Sheet 1 INVENTOR.5.

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METAL FOIL PERFORATOR FOR CAPACITOR WINDING MACHINES Filed July 8, 19484 Sheets-Sheet 2 IN V EN TORS.

METAL FOIL PERFORATOR FOR CAPACITOR WINDING MACHINES Filed July 8, 1948April 22, 1952 H. DAHL ETAL 4 Sheets-Sheet s ]NVENTOR.6

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April 22, 1952 H. DAHL ETAL 2,593,993

METAL FOIL PERFORATOR FOR CAPACITOR WINDING MACHINES Filed July 8, 194a4 Sheets-Sheet 4 17a 7 7 'Z d 53 J2g /Zm%%wm Patented Apr. 22, 1952METAL FOIL PERFORATOR FOR CAPACI- TOR WINDING MACHINES Harry Dahl andStephen T. Moreland, Indianapolis, Ind., assignors, by mesneassignments, to John E. Fast & 69., Chicago," 111., acorporation ofIllinois Application July 8, 1943, gerial No. 37 ,687

1 Claim. 1

This invention relates to the manufacture of wound electrostaticcapacitors, and has to ,do with an improved method and apparatus forperforating the strips of metal foil forming the plates of suchcapacitors, prior and preparatory to severance thereof from the supplyrolls, and as an incident to the winding operation.

A wound electrostatic capacitor comprises a roll made of two or moresuperposed elongate ribbon-like strips or Webs of metal foil,constituting the plates of the capacitor, interleaved with elongateribbon-like strips or webs of pa per or other equivalent thin flexibledielectric sheet material, the strips of foil being separated andinsulated from each other by one or more layers of papers.

For electrical reasons it is necessary that the strips of paper belonger than the strips of foil and that they overlap the foil strips atboth ends; and that requirement introduces a manufacturing problem whichwould not otherwise obtain, and the successful solution of this problemis the objective of the present invention.

Wound paper capacitors, such as are here dealt with, are required in theelectrical arts, especially radio and television, in large quantities;and in order to produce them economically they must be wound on machineswhich are, as nearly as practicable, fully automatic and adapted to runat high speeds. And, manifestly, any avoidable stopping of the machinesspells loss of production and increased production cost. Therefore, inthe interest of manufacturing economy it is essential that the strips ofmetal foil be severed without stopping or slowing down the machines-anoperation which inherently must occur prior to the severing of the paperstrips in order that the latter may overlap the foils endwise. Toaccomplish that end it has heretofore been known to perforate the metalfoils along transverse lines at the points ,of severance by means ofhigh voltage electric sparhs and thereafter, at the proper instants, toabruptly brake the foil supply reels and thus apply tension to thefoils, thereby completing the foil-severing operations along thelineso'f perforation, an example of such a construction,

being the apparatus disclosed in theKile and foratingknives, orequivalent means, whichare brought into contact with the rapidly movingfoil strips to perforate the same along transverse lines of severance,and which move with the foils until retracted out of engagementtherewith. Since there is no relative movement between the strips offoil and the perforating knives while the latter are in contact with thefoils, the perforating is accomplished as cleanly as if the foils weremotionless. Preferably, the foils are run over rubber-covered guiderolls which function as resilient moving anvils for the perforatingknives, and the latter preferablyare of small mass and, therefore, offerlittle inertia to moyement with the foils.

In the accompanying drawings there is shown, by way of example, acapacitor winding machine embodying the improvements herein to beexplained. In its general aspects the machine illustrated isapproximately identical with that which is shown and described in PatentNo. 2,205,171, above referred to.

In the drawings:

Figure 1 is an elevational view of an entire capacitor winding machinehaving incorporated therein' the features of improvement whichconstitute our present invention;

Fig. 2 is an ,elevational view of the same machine as seenfrom the righthand side of Fig. 1;

3 is an enlarged detail in elevation, taken at line -3-3 of Fig. 2,showing particularly the cam-operated switch for energizing theelectromagnets of the foil-perforating knives;

4 is an enlarged elevational View of the winding mechanism, includingthe mandrel on which the capacitors are wound;

Fig. 5 is an enlarged section, taken lengthwise along the axis of thespindles of the winding mechanismj Fig. '6 is a detail View taken atline 6- -6 of :Figl5;

Fig. '7 is a fragmentary enlarged eievational view'of the portion ofFig. 1 which includes the perforating knives and their electromagnets,showing details of the brake mechanisms whereby the" movement of thefoils is momentarily stopped to effect severance thereof shortlyaftercompletion of the perforating operation;

Fig. 3 is a plan 'view, partly in section, taken at line 8-B of Fig. 7;

Fig. 9 i ,fin enlarged detail of one of the perforating knives and itsactuating electromagnet; and

Fig. i0 is a similar view, taken at line it--Hl en 9- The windingmachine illustrated comprises a table I2 including a table top l4suppOrted on a pair ofhorizontallyspaced legs qrfuprights I 5, It,

3 and also includes an upstanding frame or panel 18 attached to andsupported on the table top It.

A countershaft 20 is bridged between and journaled on the two uprightsl5, l6 and carries a pulley 2| by means of which it is connected throughthe medium of a driving belt 22 to an electric motor 23. Saidcountershaft also carries a number of cams which perform certainfunctions later to be described, and a rotary switch-operating mechanism24, the purpose of which is to close a circuit for energizing theelectromagnets of the foil perforating knives at precisely the rightinstants.

The machine illustrated is designed and set up to produce capacitorseach comprising two strips or webs of metal foil separated by twothicknesses of paper and disposed between two outer strips or webs ofpaper. The actual machines are so designed and constructed that they maybe used to produce capacitors comprising several additional strips ofpaper; but it is not essential to a complete and adequate disclosure ofthe invention to complicate the drawing by inclusion of additional paperreels.

Both the paper and the metal foil are supplied in the form of rollstherolls of paper being identified in the drawings by reference numerals2629, inclusive, while the rolls of metal foil are identified byreference numerals 30 and 3|. Each roll, whether paper or foil, issupported on a rotatable reel or drum which, in turn, is mounted on astud secured to the panel [8.

Two strands of metal foil 30' and 3| are fed from the rolls 30 and 3|,respectively (Fig. 1), and these are guided by guide rolls 32, 33, and 33, 35 respectively, to a position at which they turn downwardly to passbetween lower guide rolls 36, 37 from which they pass further downwardlyand each capacitor are longer than the strands of metal foil, and theyoverlap the foils endwise at both ends. This means that the foils haveto be severed prior to severance of the paper by the knife 50, and thatafter severance of the foils the strands 3t, 35 must be momentarilyrestrained against further travel with the paper strands in order toproduce a suitable end-to-end spacing between the severed ends of thefoils. The severbetween a fixedly mounted roller 38 and a yieldablymounted roller 39. The two inside strands of paper '21 and 28, fedrespectively from rolls '2'! and 28, pass downwardly, in face-to-facerelation, between the two strands of metal foil 30 and 31 and the guiderolls 36, 31 and the rollers 38, 39. The outer strands of paper ,26' and29 are fed from rolls 2 6 and 29, respectively, and guided by guiderolls 4!], 4| and 42, 43 into the bight of rollers 38, 39, along withthe two inner strands of paper 21' and 2B and the two strands of metalfoil 30 and 3|. In Fig. l the lower end portions 1 of the severalstrands of paper and metal foil, designated collectively as 45, areshown terminated at a short distance below the rollers 38, 39 at thepoint 46, this being the condition obtaining immediately following thecompletion of a capacitor winding operation and, of course, immediatelyprior to the commencement of the next winding operation.

The winding of a capacitor is accomplished by means of a two-partmandrel which, at the proper time, moves up and grips the severalstrands 45 of paper and foil depending from rollers 38, 39 (Fig. 1), andthen rotates, while at the same time moving downwardly to its normalposition. This, of course, causes. the several strands of paper and foilto be paid out from their respective rolls.

Following a predetermined number of revolutions, depending upon the sizeof capacitor being made, the mandrel stops rotating and a knife isactuated automatically to sever the several strands of paper, the foilhaving already been severed, as will presently be explained, before theknife 50 is actuated.

As stated at the outset, the strands of paper of ance of the paperstrands effected by the knife 50 occurs midway between the adjacentsevered ends of the foils.

Our invention pertains primarily to the severance of the foils, each ofwhich must be perforated at transverse lines of cleavage correspondingwith the two ends of each foil of each capacitor; and it has to dospecifically with the improved arrangement and method of perforating thefoils as will now be described.

Referring more especially to Figs. 7-l0, inclusive, the guide rolls 33and 33 preferably are rubber covered; and mounted adjacent to each is anelectromagnet 52, 53, each having an armature 54, 55 to which is aiiixedan L-shaped plate 55, 51. To the lower end of each L-shaped plate 56, 51there is pivotally connected at 59, 60 a perforating knife 6!, 32, thelower edge of which is serrated, as best shown at 63 in Fig. 10, andsharpened so as to perforate the strip of metal foil passing over theguide roll 33, 35 when the electromagnet is energized. A singleoperation of the perforating knife simultaneously perforates the metalfoil at a plurality of closely spaced points extending entirely acrossthe metal foil. Normally, the armatures 54, 55 are retracted by suitablesprings 58 (Fig. 9) to maintain the serrated perforating edges of theknives 6|, 62 out of contact with the foils; but, upon energization ofthe two electromagnets, the two perforating knives are moved for a briefinstant into contact with the two foils, the rubber coverings of theguide rolls 33, 35 acting as yieldable anvils to receive the blows ofthe knives whereby their teeth are permitted to penetrate the foil so asto produce clean cuts, while at the same time not dulling or bluntingthe sharpened knife teeth. Wire springs 64, 65 are anchored respectivelyto the armatures 5d, 55 and bear at their distal ends against the knivesGI, (52, thereby yieldably holding the knives in their normal posturesas per the full line showing of Fig. 9. When the perforating knivesstrike the moving strips of foil, their serrated edges are carried alongwith the foil to a position such as that indicated in dotted outline inFig. 9, the knives being rotated as a result, about their fulcrums 59,69; but the duration of each energization of electromagnets 52, 53 is sobrief that before the serrated edges can be carried any considerabledistance by the foils the knives are retracted. The knives are of smallmass and the springs 64 are light so that there is extremely littleresistance to the movement of the serrated edges of the knives with thefoils; also there is no apparent tendency to tear the foils.

The windings of the two electromagnets 52, 53 are included in a commonenergizing circuit, in which is also included a normally open switch 66(Fig. 3) having an operating lever 6?, bent to provide a cam surface 38which lies in the path of a lug ll] carried by a disc 12 which issecured to the countershaft 20. The disc 72 can be rotatively adjustedon the countershaft 20 so as to change the timing of the switch 66; andthe lattit ter is carried by a plate 14 which is rotatably adjustable,thus providing for fine adjustments of the time of energization of theelectromagnets 52, 53. Adjustments of the plate 14 are effected by meansof an adjusting screw 16 provided with a hand wheel 11 (Fig. 1).

When the lines of severance in the two foils, formed by theperforations, have traveled downwardly from the guide roll 33, 35 to asuitable position adjacent the rollers 38, 33, brakes are applied for aninstant to the reels which carry the rolls 3H and 3! of metal foil, andthe resultant added tension severs the two strips of foil at theperforated lines of severance. The brakes are kept on just long enoughto permit the severed ends of the foil to separate to whatever extentmay have been determined upon, and then the cutting-off knife 50 isactuated to sever the four strips of paper along a line midway betweenthe severed ends of the foils. The brakes are then released to permitthe two strips of foil to be carried along with the paper strips.

The reels for the two rolls of metal foil and the brake mechanismtherefor are shown in detail in Figs. '1 and 8. The reels are identifiedby the reference numerals 80, 8|, and rotatably mounted on studs 82, 83,which are detachably secured to the panel I3. The rolls 30 and 3| ofmetal foil are held in place on their reels by means of flanged sleeves04, 85 which are pressed endwise against the rolls of foil by coilsprings 86, 81, held in place by nuts 88, '89. Each reel 30, BI has anintegral brake drum 90, 9|, each arranged to be acted upon by a pair ofbrake arms 92, 33 and 94, 35, which are adapted to becontracted intoengagement with the respective brake drums by the linkages 96, 91, theoperation of which is self-evident from Fig. '1. Springs 93, 90 serve toactuate the brakes. The two linkages 96, 91 are connected by means ofcables I03, It to a :bellcrank I02, to which also is connected a cableI03 which normally is maintained under tension in opposition to thesprings 98, 99, to thus hold the brakes inactive. The lower end of thecable I63 is connected to a rigid curved arm I04, the lower end of whichis rigidly connected to a lever I05, Fig. 1, which bears against theperiphery of a cam disc 53 locked to the countershaft 20 and having anotch 58' which allows the coacting lever I05 to move upwardly for abrief instant during each revolution of the shaft 29. This releases thetension on the cable I03, and consequently allows the brakes to beapplied by the springs 38, 93.

The mandrel upon which the capacitors are wound is shown in detail inFigs. 4 and 5 and consists of a rigid mandrel section I06 and a movablemandrel section I01. These mandrel sections are raised and lowered, asshown in the full and dotted line positions of Fig. 4. The mandrelsection I01 is movable from the open or dotted line position of Fig. 5to the closed position indicated by full lines therein. When the mandrelcomes to rest in the full line position of Fig. 4, the fixed mandrelsection I06 lies at the rear of the depending multiple strand 45, whilethe movable mandrel section lies on the opposite side. By raising themandrel sections bodily from the full line position of Fig. 4 to thedotted line position, and then by closing the movable section I01, thetwo sections are caused to grip the depending multiple strand &5 betweenthem. The method of raising and lowering the mandrel sections will laterbe described.

The fixed mandrel section I05 is carried by a fixed mandrel head H0which is secured to a shaft I I I journaled in a suitable bearinghousing H2 that is carried on a platform H3. This platform is movable upand down as will later be explained, and as shown in full and dottedlines in Fig. 4. In these movements the platform is guided on rods H4slidably fitted in guides Ma on the table top i l. The method of raisingthis platform will later be explained, and also the means for grippingthe outer end of the mandrel section I01.

The shaft I I i is secured against endwise movement and has a bevelpinion H6 meshing with a bevel gear I I1. The latter is keyed to a shaftI I8 which is journaled in suitable bearings I I9. The shaft H8 isdriven from the countershaft 20 through a drive chain I23 and a variablespeed transmission I22 (Fig. l) which includes an interrupted gear I2 3.Thus it will be seen that with the countershaft 20 running at a constantspeed, the mandrel shaft III will be driven at a reduced speed part ofthe time and at an accelerated speed part of the time. The proportion ofthe total time during which the mandrel will remain stationary dependsupon the design of the interrupted gear I25. Likewise, the number ofturns that the mandrel shaft I I I will make per revolution of thecountershaft 20 depends upon the gears making up the gear train, but isfixed by each gear train. The Geneva gear train comprising theinterrupted gear I2 l insures that the mandrel I06 will stop at the sameposition each time.

The movable mandrel section I01 (Figs. 4 and 5) is secured to a blockI26 which is pivotally mounted by a pin I21 on a mandrel head I28, thelatter being carried by a stub shaft I30 which is journaled in a shaftI3 5, rotatably and slidably journaled in a sleeve I32 that is carriedby a support I33 on the platform H3. A rod I34 forms a reduced sectionof the shaft I3I and has adjustably mounted thereon a collar I35 towhich is secured one end of a tension spring I36, the opposite end beingconnected to a yoke I31 which has a straight portion I31a slidablymounted in suitable bearings I38, and has a block I 39 adjustablymounted on its opposite end. A tension spring I40 is connected at oneend to the block I39 and at the other to a pin MI on the platform H3.The yoke I31 is bifurcated and engages an annular groove I42 in a sleeveI43, the latter being slidable over the shaft I3I and the mandrel headI28. The sleeve I i-3 bears against a pin I44 in the block I26. Atension spring I45 holds the pin I44 against the sleeve.

The spring I40 tends to hold the various parts in the full line positionof Fig. 5 in which the mandrel sections are in overlapping relation andare locked together as will hereinafter be explained. A flexible memberHi5 (Fig. l) is connected to the yoke I31 and passes over suitablesheaves I41, I43 and over another sheave (not shown) on a lever Hi9which is adapted to be actuated by a cam I55 (Fig. 2) on thecountershaft 20. The spring I40 tends to hold the parts shown in Fig. 4against the tension of the flexible member I45 so as to maintain thelatter taut at all times. As the cam I rotates it acts through theflexible member I46 to draw the mandrel section I31 from the positionshown in Fig. 5 to the position shown in Fig. 4, and as the camcontinues to rotate the spring I40 returns it to the position of Fig. 5.

The mandrel head I23 is adapted to receive the end of the mandrelsectionI06 as it is moved .is locked to the shaft 20. remains in the full lineposition for more than cam III, acting on thelink I68, lifts theplataseaees to the right in Fig. 5, while the section I01. is still inthe open or dotted line position, due to the fact that the spring I36has forced the shaft I3I and the mandrel section I'I to the full lineposition of Fig. but the flexible member I46 acts to hold the sleeve I43in the dotted line position of Fig. 5 until, with advance of the camI50, the flexible member I46 permits the spring I40 to return the sleeveI43 to the full line position of Fig. 5, thereby moving the mandrelsection I01 into the full line position of Fig. 5, and at the same timegripping the outer end of the mandrel section I06.

At the same time, the shaft III which carries the mandrel head H0 andthemandrel section I06 also carries a sliding mandrel head I5I which isslidably mounted on the mandrel head I I0 and has a recess I52 adaptedto overlie and engage the outer end of the mandrel section 01 in thefull line position of Fig. 5 when the sliding mandrel head I5I is forcedto the left as there shown.

This movement takes place after the two mandrel sections are closed. Thesliding mandrel head IEI has an annular groove I53 therein in which isslidably mounted a yoke I56 having a rod I55 which is slidabl mounted inthe bearing housing H2 and parallel to the shaft III. A spring I56between the housing and the sliding mandrel head normally forces thelatter outwardly to the position shown in Figs. 4 and 5. A flexiblemember I5? is secured at one end to the yoke i5 1 and passes oversuitable sheaves I50, I59 (Fig. 4) and is connected to a lever I60 (Fig.2) which is pivotally connected to the table supports. The lever I60 isheld in contact with a cam I62 (Fig. 2) on the countershaft 20 by meansof a tension spring IE3. Thus, at a predetermined point in the rotationof the countershaft 20, the cam I52 draws the sliding mandrel head I5Iback against the action of the spring I56 and holds it there until thelever I60 suddenly drops off the point of the cam, thereby releasing thehead I5I which is then returned by the spring I56 to the full lineposition of Fig. 5, thereb locking the end of the mandrel section I0!which has just closed to the full line position of Fig. 5. It is openjust long enough to allow the mandrel section E0? to close and then beengaged.

For raising the platform I I3 from the full line position to the dottedline position of Fig. 4, the platform is provided with a centrallylocated pin H34 which passes through the table I I and is adapted to beengaged by a screw I65 adjustably carried by a lever I68, which isfulcrumed to the- 0 table I4, the opposite end being pivotally connectedto a link I68. The shaft 20 passes through a slotted opening in the linkI58 so that the link is guided thereby. The link carries a cam followerwhich rides on a cam I'lI which Thus, the platform I I3 half eachrevolution of the shaft, but is raised to the dotted line position for apredetermined portion of each revolution.

Starting with the parts as shown in full lines in Fig. 4, the mandrelsection I06 lies back of the depending ends 55 of the paper and foilstrands which go to make up the capacitor. The mandrel section I 07 isretracted and open as shown in dotted lines in Figs. 4 and 5. As theshaft 2i; rotates, the cam I50 permits the flexible member M6 to bedrawn back, thereby forcing the shaft I3I to the right. t the same timethe form II3 from the full line position of Fig. 4 to the position shownin dotted lines therein. In this latter position the two mandrelsections I06 and I0! lie one on each side of the lower ends of thedepending strands 45. At this time the sliding mandrel head I5I (Fig. 5)is retracted, as previously described. As the yoke I31 continues to moveto the right, the shaft I3I moves with it until the collar I35 strikesthe sleeve I32. This fixes the movement to the right of the mandrelsection I01. The mandrel head I5I then is moved by the spring I56, aspreviously described, to lock the mandrel section I0'I.

As the yoke I31 continues to move to the right, it stretches the springI36 and moves the mandrel section II" from the dotted line position ofFig. 5 to the full line position, thereby causing the sleeve I43 toengage the pin IM and to close the mandrel section I0! on the mandrelsection I06. The cam I62 then releases the tension on the flexiblemember I51, thereby permitting the spring I56 to return the slidingmandrel head I5I tothe position shown in Fig. 5 in which, as previouslydescribed, it engages and locks the outer end of the mandrel section I0!to the mandrel section I06. At the same time the outer end of themandrel section I06 is locked to the mandrel section I07 in the mandrelhead I28. Following this, the mandrel shaft III is driven by the geartrain I22. The two mandrel sections are locked together and are drivenfrom the shaft III, the mandrel head I28 rotating on its own stub shaftI30. This stub shaft is held in the shaft I 3I by means of a dog pointset screw I300, in the shaft I3I.

As the mandrel sections I06, I 01 rotate, the paper and foil strips arewound about the mandrel, suitable tension being maintained on each stripby means of drag brakes applied to the respective rolls of paper andfoil. As the winding continues, the cam I'II rotates so as to return theplatform H3 to its lowered position. The winding then proceeds so longas the mandrel is'driven by the toothed portion of the gear I 24. Whenthe winding is nearly complete, the metal foil strips are perforated, aspreviously described, and the brakes are thereafter applied to the brakedrums 95, SI, to sever the metal foils, also as previously described;and the knife 50 is then actuated to cut the several strands of paper,thereby detaching the finished capacitor. The mandrel shaft II I thenstops, and immediately thereafter the mandrel section I0! is withdrawnfrom the fully wound capacitor which is retained on the mandrel sectionI06 by two spaced stripping fingers I72 (Fig. 2).

While the shaft II I and the mandrel section I06 remain at rest, thefully wound capacitor is taped or glued by an operator, to preventunwinding, and manually removed; or it may be secured and removed byautomatic means, not shown.

It is obvious that various changes may be made in the specificembodiments set forth for purposes of illustration without departingfrom the principles of the invention. The invention is accordingly notto be limited to the precise details disclosed herein but includes allmodifications thereof within the spirit and scope of the appended claim.

We claim:

In a capacitor winding machine, a mechanism for perforating a movingstrip of metal foil at preselected intervals comprising a rotatablymounted guide roller carried by said machine and over which the foil ispassed, said guide roller having a rubber-like covering providing aresilient backing surface for frictional contact With the foil, saidroller being so disposed relative to said machine that the foil is infrictional contact with a substantial circumferential por tion of theroller covering, perforating means carried by said machine injuxtaposition to said guide roller, said perforating means including aperforating tool having a perforating edge disposed transversely of andnormally in substantially perpendicular relation to a plane tangentialto said guide roller intermediate the ends of said circumferentialportion, said perforating tool normally being out of contact with saidguide roller, electromagnetic means carried at one end by said machineand with said one end in juxtaposition to said guide roller, an armaturepivotally disposed adjacent the other end of said electromagnetic meansand normally resiliently retained out of contact therewith, saidarmature being movable responsive to actuation of the electromagneticmeans toward the latter means and the guide roller, and an L-shapedplate carried by said armature for movement therewith and pivotallysupporting said perforating tool, actuation of said electromagneticmeans effecting movement of said perforating tool toward said guideroller so that the perforating edge of the perforating tool penetratesthe foil, the rubberlike covering providing a yieldable anvil backingthe foil, and the perforating edge of the tool being movable with thefoil and pivoted out of contact with the foil upon continued movement ofthe foil, deactuation of the electromagnetic means effecting retractionof the perforating tool.

HARRY DAHL.

STEPHEN T. MORELAND.

REFERENCES CITED The followingreferences are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 652,754 Davis July 3, 1900938,441 Shelton Oct. :26, 1909 1,931,979 Chandler Feb. 25, 19312,142,728 Kienzle Jan. 3, 1939 2,205,171 Kile et al June 18, 19402,235,948 Schwisow Mar. 25, 1941 2,333,024 Mathes Oct. 26, 1943

